A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the derm...A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the dermis structure and the properties of finished leather. The use of finely-dispersed minerals promotes alignment of topographic areas in thickness, increases the yield of leather on the area by avoiding bonding structural elements of the dermis. Changes in the microstructure of the dermis, as a result of mineral filling, contribute to improvement of performance and hygienic properties of finished leather. And the study of the properties of the specified skins should be consistent with the features of operations on their cutting, shoe molding and shoe upper fixing preparations. The most important properties of leather materials, which largely determine the quality of basic technological operations of shoe manufacturing are the deformation properties. Lack of information about relaxation and deformation properties of the leather produced by the new technologies do not allow to predict their ability to form shapes and save it--indicates the relevance of this study. This paper analyzes relaxation and deformation characteristics of natural leather for shoe uppers, filled with natural minerals montmorillonite and zeolite, and the ability to predict their formation and preservation of shape in service. Features of deformation of the skin with mineral content were assessed by determining single-cycle characteristics when attaching to a complete test cycle ＂loading-unloading-rest＂ sample. Correlations of elastic and plastic （permanent） deformation have been established, kinetics of changes in linear characteristics of the samples after removal of the load has been investigated. Introduction of dispersions of mineral to the structure of the dermis contributes to the strength of semi-finished leather, increase of the uniformity of mechanical properties in the longitudinal and transverse directions and rise of shape stability index. It is shown that the direction of this study allows us to offer new competitive ecologically friendly materials to produce shoes.展开更多
The Chinese alligator Alligator sinensis is one of the most endangered crocodilian species, and typically exhibits temperature-dependent sex determination. It is extremely important to clarify the sex structure of Chi...The Chinese alligator Alligator sinensis is one of the most endangered crocodilian species, and typically exhibits temperature-dependent sex determination. It is extremely important to clarify the sex structure of Chinese alligators to implement recovery projects successfully. However, the sex ratio of wild Chinese alligators remains unknown. In this study, we collected 28 years of sex ratio data from Chinese alligators residing in the natural and artificial habitats of Changxing Nature Reserve, China, and examined the differences in the sex ratio dynamics between these two populations. We observed that the sex ratio of wild Chinese alligators is 1 male to 4.507 females, which was significantly lower compared to that of the captive population （1 to 2.040; P 〈 0.001）, and is significantly different to previously documented sex ratios for this species （all P 〈 0.01）. Furthermore, we documented an annually stable （P = 1.000） female-biased sex ratio for wild alligators at hatching [1 male to 4.747 females; 0.174 （0.167~）.182）], in contrast to a dramatically fluctuating sex ratio （P 〈 0.001） in captivity [1 male to 1.674 females; 0.374 （0.246-0.593）], showing a potential mechanism for adjusting the sex structure. Finally, we found that the hatchling sex ratios were similar to that of the population sex ratio （P = 0.748）, with little correlation to air temperature values in the 60-70 day incubation period during the breeding season （July and August; both P 〉 0.05）. Overall, this study indicates that the stabilized female-biased sex ratio of Changxing Chinese alligators might result from selection pressure caused by local mate competition and major inbreeding .展开更多
supported by the Taishan Scholar Construction Engineering by Shandong Government the National Natural Science Foundation of China under Grant Nos.61120106011 and 61203029
文摘A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the dermis structure and the properties of finished leather. The use of finely-dispersed minerals promotes alignment of topographic areas in thickness, increases the yield of leather on the area by avoiding bonding structural elements of the dermis. Changes in the microstructure of the dermis, as a result of mineral filling, contribute to improvement of performance and hygienic properties of finished leather. And the study of the properties of the specified skins should be consistent with the features of operations on their cutting, shoe molding and shoe upper fixing preparations. The most important properties of leather materials, which largely determine the quality of basic technological operations of shoe manufacturing are the deformation properties. Lack of information about relaxation and deformation properties of the leather produced by the new technologies do not allow to predict their ability to form shapes and save it--indicates the relevance of this study. This paper analyzes relaxation and deformation characteristics of natural leather for shoe uppers, filled with natural minerals montmorillonite and zeolite, and the ability to predict their formation and preservation of shape in service. Features of deformation of the skin with mineral content were assessed by determining single-cycle characteristics when attaching to a complete test cycle ＂loading-unloading-rest＂ sample. Correlations of elastic and plastic （permanent） deformation have been established, kinetics of changes in linear characteristics of the samples after removal of the load has been investigated. Introduction of dispersions of mineral to the structure of the dermis contributes to the strength of semi-finished leather, increase of the uniformity of mechanical properties in the longitudinal and transverse directions and rise of shape stability index. It is shown that the direction of this study allows us to offer new competitive ecologically friendly materials to produce shoes.
文摘The Chinese alligator Alligator sinensis is one of the most endangered crocodilian species, and typically exhibits temperature-dependent sex determination. It is extremely important to clarify the sex structure of Chinese alligators to implement recovery projects successfully. However, the sex ratio of wild Chinese alligators remains unknown. In this study, we collected 28 years of sex ratio data from Chinese alligators residing in the natural and artificial habitats of Changxing Nature Reserve, China, and examined the differences in the sex ratio dynamics between these two populations. We observed that the sex ratio of wild Chinese alligators is 1 male to 4.507 females, which was significantly lower compared to that of the captive population （1 to 2.040; P 〈 0.001）, and is significantly different to previously documented sex ratios for this species （all P 〈 0.01）. Furthermore, we documented an annually stable （P = 1.000） female-biased sex ratio for wild alligators at hatching [1 male to 4.747 females; 0.174 （0.167~）.182）], in contrast to a dramatically fluctuating sex ratio （P 〈 0.001） in captivity [1 male to 1.674 females; 0.374 （0.246-0.593）], showing a potential mechanism for adjusting the sex structure. Finally, we found that the hatchling sex ratios were similar to that of the population sex ratio （P = 0.748）, with little correlation to air temperature values in the 60-70 day incubation period during the breeding season （July and August; both P 〉 0.05）. Overall, this study indicates that the stabilized female-biased sex ratio of Changxing Chinese alligators might result from selection pressure caused by local mate competition and major inbreeding .
基金supported by the National Natural Science Foundation of China under Grant Nos.71125005,70871108,and 70810107020Outstanding Talents Funds of Organization Department,Beijing Committee of CPC
文摘supported by the Taishan Scholar Construction Engineering by Shandong Government the National Natural Science Foundation of China under Grant Nos.61120106011 and 61203029
